Definition

Hypertrophic cardiomyopathy, or HCM, is a form of
cardiomyopathy. This is a condition in which the heart muscle thickens due to genetic problems with the muscle’s structure. As the muscle thickens, it must work harder to pump blood, which strains the heart muscle. Sometimes, the thickened muscle gets in the way of the blood leaving the heart and causes a blockage. This blockage can cause the nearby heart valve, called the mitral valve, to become leaky. HCM can cause uneven muscle growth which can cause the heart to pump in a disorganized way. Rarely, it can cause abnormal heart rhythms that can even be fatal.

There are three main types of cardiomyopathy:

Dilated

Hypertrophic—can be divided into two types:

Hypertrophic obstructive cardiomyopathy (HOCM)—the muscle between the two valves of the heart becomes so enlarged that it obstructs the blood flow in the heart

Non-obstructive hypertrophic cardiomyopathy—non-obstructive form, the enlarged muscle is not large enough to block blood flow

Risk Factors

HCM can occur in people of all ages. But, it is usually most severe when it occurs in younger people.

These factors increase your chance of developing this condition. Tell your doctor if you have any of these risk factors:

Having a family member with HCM

Being over age 60 and having hypertension

Symptoms

Symptoms include:

Chest pain

Fainting, particularly during exercise

Lightheadedness, particularly following exercise

Rapid heartbeat

Shortness of breath or difficulty breathing

General fatigue

Tiring easily during exercise or activity

Shortness of breath when lying down

These symptoms can be caused by some of the side effects of the condition, including
arrhythmias
(abnormal heart beats). The blocked or reduced blood flow is usually the cause of symptoms like lightheadedness, fainting, and difficulty breathing.

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done.

Your bodily fluids may be tested. This can be done with blood tests.

Your body's response to exercise may be tested. This can be done with a stress test.

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